The present invention relates to a new and distinct cultivar of dahlia that is grown for use in mixed combinations, beds and the landscape. The new invention is known botanically as Dahlia variabilis and will be referred to hereinafter by the cultivar name ‘KNOCKOUT’. The specific epithet variabilis represents a hybrid seedling line that came from crossing various original wild species in the early 1800's, and refers to the species' wide range of flower color and shapes. Dahlia is in the family Compositae. The inflorescence of ‘KNOCKOUT’ is a “single” form blossom and exhibits a single row of ray florets surrounding a central cluster of disk florets.
‘KNOCKOUT’ was selected by the inventor as a seedling that resulted from the controlled cross-pollination carried out by the inventor in a cultivated area of Auckland, New Zealand. The breeding began in 2001 by crossing an individual unpatented Dahlia variabilis named 71157/01 as the female parent and an individual Dahlia variabilis from the inventor's experimental F1 Lines as the male parent. The female parent was planted in associated with dahlia plants that exhibited similar characteristics. Seed was collected from the female parent and coded as 71334/01, then sown with the intention of making a selection from the seedlings that resulted.
‘KNOCKOUT’ was selected in 2002 based on the criteria of leaf color and clarity of flower color. Selection was conducted by the inventor, in Auckland, New Zealand. The unique traits that distinguish the new Dahlia variety named ‘KNOCKOUT’ from other varieties of the same genus are mahogany-black divided leaves and profusions of vivid yellow star-shaped blossoms. The new Dahlia named ‘KNOCKOUT’ is distinguishable from the parents by the clarity of bloom color and darkness of the leaves.
‘KNOCKOUT’ exhibits upright habit, large mahogany-black buds, fragrant yellow inflorescences, and mahogany-black foliage. The large star-shaped blossoms bloom in summer and fall. Cultural conditions include full sun, regular water and rich well-draining potting soil. ‘KNOCKOUT’ is hardy to USDA Zone 8 and grows to 0.9 m in height and 0.9 m in width at maturity.
The first asexual reproduction of ‘KNOCKOUT’ was conducted in 2004 in Auckland, New Zealand. The method of asexual propagation utilized was tissue culture. Since that time under careful observation, the distinguishing characteristics have been determined stable, uniform, and to be reproduced true to type in subsequent generations of asexual propagation.